I haven't read anywhere directly saying that the Celtics are interested in Jonny Flynn, but it is clear from Danny's comments below that he's looking at overseas options. Putting two and two together...

Ainge, Celts put on guard | Boston Herald

We have players we like in the D-League, and we have a little more than a week before the trade deadline. And we’ll explore all of that. "Immediately we will probably bring someone in on a 10-day contract, and we’re going through all those names. There’s a lot of names actually, but it’s going to be very difficult to replace Leandro Barbosa." "Immediately" will likely mean the end of the All-Star break that starts tomorrow, and in terms of free agents, the Celtics are looking beyond the D-League and the U.S. border. "There are guys playing all around the world, and I need to figure out when they may become available with their contracts," said Ainge. "So there’s a lot to go through here."

He also says that he wants guys that can be an impact the way Barbosa could be at times. There are tons of guys that can play in the NBA. Few of them have the upside talent to be "impact" guys. One guy that immediately comes to mind is Jonny Flynn.